body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
    max-width: 600px;
    margin: 0 auto;
    padding: 20px;
    color: #333;
}

h1 {
    text-align: center;
    color: #007AFF;
}

.container {
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.preview {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 10px;
}

#imagePreview {
    max-width: 200px;
    max-height: 200px;
    border: 1px dashed #ccc;
}

button, .convert-btn {
    background-color: #007AFF;
    color: white;
    border: none;
    padding: 10px 15px;
    border-radius: 5px;
    cursor: pointer;
}

button:hover, .convert-btn:hover {
    background-color: #0062CC;
}

.download-icon {
    width: 16px;
    height: 16px;
    fill: white;
    margin-right: 8px;
    vertical-align: middle;
}

select, input {
    padding: 10px;
    border: 1px solid #ccc;
    border-radius: 8px;
    background-color: white;
    transition: all 0.3s ease;
}

select:hover, input:hover {
    border-color: #007AFF;
}

select:focus, input:focus {
    outline: none;
    box-shadow: 0 0 0 2px rgba(0, 122, 255, 0.2);
}

.container > div {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 10px;
}

.all-sizes-option {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 10px;
}

.all-sizes-option input[type="checkbox"] {
    appearance: none;
    width: 18px;
    height: 18px;
    border: 2px solid #007AFF;
    border-radius: 4px;
    cursor: pointer;
    position: relative;
    transition: all 0.2s ease;
}

.all-sizes-option input[type="checkbox"]:hover {
    border-color: #0062CC;
}

.all-sizes-option input[type="checkbox"]:checked {
    background-color: #007AFF;
    border-color: #007AFF;
}

.all-sizes-option input[type="checkbox"]:checked::after {
    content: "";
    position: absolute;
    left: 5px;
    top: 1px;
    width: 5px;
    height: 10px;
    border: solid white;
    border-width: 0 2px 2px 0;
    transform: rotate(45deg);
}

.all-sizes-option label {
    cursor: pointer;
    user-select: none;
}

.drag-drop {
    border: 2px dashed #ccc;
    border-radius: 5px;
    padding: 20px;
    text-align: center;
    width: 100%;
    transition: all 0.3s;
}

.upload-icon {
    width: 48px;
    height: 48px;
    fill: #ccc;
}

.drag-drop.highlight {
    background-color: rgba(0, 122, 255, 0.1);
    border-color: #0062CC;
}

.file-name {
    margin-top: 10px;
    color: #333;
    font-size: 14px;
}